Method and Apparatus for Session Management Function Selection

1. A method performed by an Access and Mobility Management Function (AMF) of a serving network, comprising: receiving a requested Network Slice Selection Assistance Information (NSSAI) from a wireless communication device visiting the serving network; sending a network slice instance (NSI) selection request message to a first database that maintains function information pertaining to at least one NSI, wherein the NSI-selection request message comprises the requested NSSAI, and an indication that a requested data session is home routed through a home network of the wireless communication device; receiving a NSI-selection response message from the first database, wherein the NSI selection response message comprises, in response to the indication, an address of a network function repository function (NFRF) in the home network; selecting a first session management function associated with a NSI of the serving network; and selecting a second session management function associated with a NSI of the home network.

2. The method of claim 1 further comprising: sending a first session management function selection request message to a second database; receiving a first session management function selection response message, wherein the first session management function is selected based on the first session management function selection response message; enabling a second session management function selection request message to be sent to a third database; and receiving a second session management function selection response message, wherein the second session management function is selected based on the second session management function selection response message.

3. The method of claim 1 , wherein the NSI selection response message comprises slice information of the home network.

4. An apparatus of a serving network, comprising: at least one processor and a memory coupled to the at least one processor, the at least one processor configured to: receive a requested NSSAI from a wireless communication device visiting the serving network; send a network slice instance (NSI) selection request message to a first database that maintains function information pertaining to at least one NSI, wherein the NSI selection request message comprises the requested NSSAI and an indication that a requested data session is home routed through a home network of the wireless communication device; receive a NSI selection response message from the first database, wherein the NSI selection response message comprises, in response to the indication, an address of a network function repository function (NFRF) in the home network; select a first session management function associated with a NSI of the serving network; and select a second session management function associated with a NSI of the home network.

5. The apparatus of claim 4 , wherein the at least one processor is further configured to: send a first session management function selection request message to a seeond database; receive a first session management function selection response message, wherein the first session management function is selected based on the first session management function selection response message; enable a second session management function selection request message to be sent to a third database; and receive a second session management function selection response message, wherein the second session management function is selected based on the second session management function selection response message.

6. The apparatus of claim 4 , wherein the NSI selection response message comprises slice information of the home network.

7. A non-transitory computer-readable medium having computer-executable instructions stored thereon, the computer-executable instructions, when executed by a processor of a serving network, causing the processor to perform: receiving a requested Network Slice Selection Assistance Information (NSSAI) from a wireless communication device visiting the serving network; sending a network slice instance (NSI) selection request message to a first database that maintains function information pertaining to at least one NSI, wherein the NSI selection request message comprises the requested NSSAI, and an indication that a requested data session is home routed through a home network of the wireless communication device; receiving a NSI selection response message from the first database, wherein the NSI selection response message comprises, in response to the indication, an address of a network function repository function (NFRF) in the home network; selecting a first session management function associated with a NSI of the serving network; and selecting a second session management function associated with a NSI of the home network.

8. The non-transitory computer-readable medium of claim 7 , wherein the computer-executable instructions, when executed by a processor, further causing the processor to perform: sending a first session management function selection request message to a second database; receiving a first session management function selection response message, wherein the first session management function is selected based on the first session management function selection response message; enabling a second session management function selection request message to be sent to a third database; and receiving a second session management function selection response message, wherein the second session management function is selected based on the second session management function selection response message.

9. The non-transitory computer-readable medium of claim 7 , wherein the NSI selection response message comprises slice information of tag home network.